A web app nomogram based on real-life patients: Guide decision in first-line treatment for metastatic castration-resistant prostate cancer (mCRPC)

e17538 Background: mCRPC phenotype involves androgen-receptor signalling mechanisms that support the use of abiraterone/enzalutamide (Abi/Ez). These therapies improve overall survival (OS) and quality-of-life, with a favourable safety profile. There is no validated data defining the best drug or sequence to be used. Methods: A retrospective study evaluated if a nomogram helps the decision-making of first-line for mCRPC. The nomogram evaluated time-to-treatment failure (TTF) from Abi/Ez and Docetaxel (Doc) treatment and had C-índex of 0.726. Time from start of androgen deprivation therapy to Abi/Ez or Doc, pain, Gleason score, testosterone and the lowest PSA in castration-sensitive scenario were analysed. All patients (pts) in Doc group used second-line Abi/Ez. The outcomes were: to evaluate whether the nomogram scores were associated with TTF/OS in Abi/Ez population; to compare OS between Abi/Ez and Doc poor prognostic (PP) groups based on the nomogram scores. Kaplan-Meier and Cox-regression models were used for time-to-event analyses. The cut-off was defined by Log-Rank. Statistical significance was fixed at 0.05. Results: From May/12 to Feb/20, 123 pts were assessed (79 received first-line Abi/Ez and 44 Doc). Median follow-up was 25.7 months (1.6 to 93.7). Nomogram scores based on Abi/Ez treatment (medium score of 65, 0-225) were statistically associated with OS (HR 1.02, 95% CI 1.01-1.02, p < 0.001) and TTF (HR 1.02, 95% CI 1.02-1.03, p < 0.001). 79 pts who received Abi/Enz were stratified as having good (GP) (score < 46), intermediate (IP) (score 46-112) and PP (score > 112), and it was associated with 75%, 25-75% and 25% probability to 1-year free from treatment failure, respectively. Pts with GP (n = 24) had a median TTF of 29.8m (15.4-44.2), IP (n = 44) 9.8m (4.1-15.4) and PP (n = 11), 4m (2.5-5.5), p = < 0.001. Pts with GP achieved higher TTF than IP (HR 2.3 95% CI 1.3-4.2 p = 0.005) and PP (HR 8.9 95% CI 3.8-20.6 p < 0.001). The results were similar for OS, once the median for GP was 54.0m (30.5-77.6); IP 34.8m (32.2-37.5); and PP 13.6m (9.3-17.9), p = 0.023 (GP versus IP: HR 2.1 95% CI 1.01-4.4 p = 0.046; GP vs PP: HR 3.6 95%CI 1.4-9.6 p = 0.011). Pts with a higher score and PP from Abi/Ez group were compared with Doc pts at first-line (n = 44), showing worse OS (HR 2.4 95%CI 1.03-5.6 p = 0.042) when treated with Abi/Ez. Conclusions: The nomograns scores showed good correlation with TTF/OS. In PP groups, treatment with Doc was associated with better OS than Abi/Ez, suggesting a possible tool on the first-line decision making.